Lead is a heavy metal extremely harmful to human health. With unique physical and chemical properties, lead is widely used in the human society. However, it is also a toxic metal element harmful to a plurality of organs of human, and has no physiological effect in the human body. Therefore, the ideal blood lead concentration should be zero. With rapid development of the industry, agriculture, transportation, paint, printing and electronics industry, lead contaminates the air, soil, water and foods to different extents. The exposure to lead for a long time of gradual contact makes people absorb more lead, resulting in lead accumulation in the body. Lead can directly damage the human health, especially the nervous system, kidneys, hematopoietic system, vascular system and so on. Lead toxicity causes symptoms such as abdominal pain, diarrhea, vomiting, headache, dizziness, coma, and other symptoms, accompanied with vasospasm, liver and kidney damage and other physiological disorders.
Chelating agents such as EDTANa2Ca and dimercaptosuccinate sodium are most commonly used for the alleviation of lead toxicity. For example, the Chinese Pharmacopoeia, Edition 2 (2000) describes that EDTANa2Ca is used as an antidote for heavy metal toxicity such as lead and cadmium. However, these drugs have certain side effects. The said calcium EDTA is a chelator with broad spectrum and strong renal toxicity. Moreover, if the drug containing EDTANa2Ca is administered, a large number of essential trace elements for human body such as zinc, copper, manganese, iron and so on will be excreted with the urine. As these elements are tightly related with the activities of many enzymes, the chelators will endanger human health if used for long time.
For these problems of traditional therapies, it is necessary to find a new intervention or treatment method for lead accumulating and lead toxicity. Lactobacilli are collectively referred to a class of bacteria that can ferment carbohydrates to produce lactic acid. It is widely found in naturally fermented dairy products, fermented plant foods such as pickles, sauerkrauts, silages, and the human intestine. Studies have shown that probiotics including lactobacilli are beneficial bacteria which are essential for the human body and have important physiological functions. The beneficial effects of lactobacilli mainly include: preventing lactose intolerance, tumor and cancer; balancing the human intestinal microflora; promoting the detoxification function of liver and so on. With the exploration of new probiotic functions of lactobacilli, we can put forward some new methods and solutions to alleviate lead toxicity through dietary strategies.
Therefore, it is necessary to screen lactobacilli with the ability of alleviating lead toxicity, and prove that they can play a good role in alleviating lead toxicity in animal models. The applications of these lactobacilli should be developed as well.